A DAS can be used to extend wireless coverage in an area through the use of one or more repeaters and multiple remote units coupled to each repeater. Repeaters can be coupled to one or more base stations that can each manage wireless communications for different cell sites. A repeater can receive downlink signals from the base station and distribute downlink signals in analog or digital form to one or more remote units. The remote units can transmit the downlink signals to user equipment devices within coverage areas serviced by the remote units. In the uplink direction, signals from user equipment devices may be received by the remote units. The remote units can transmit the uplink signals received from user equipment devices to the repeater. The repeater can transmit uplink signals to the serving base stations.
A base station can include a digital baseband unit and a radio transceiver unit that communicate using a digital optical interface. Industry communication standards, such as the Open Base Station Architecture Initiative (“OBSAI”) or Common Public Radio Interface (“CPRI”) standards, can be used to implement the digital optical interface between the digital baseband unit and radio transceiver unit. For example, the baseband unit of a base station can include several CPRI output ports. Each port can be input into various radio transceiver units.
The radio transceiver units of the base station can interface with a repeater using a radio frequency communication link. To communicate with the repeater, each radio transceiver unit in the base station can include hardware for signal processing and digital-to-analog conversion of incoming single carrier I/Q and control data streams to RF signals output at antenna ports. The use of a radio frequency communication link between the base station and the repeater can lead to higher equipment costs and increased power consumption due to the signal processing for digital-to-analog conversion and high powered RF amplification.